Method of and apparatus for open-end spinning

ABSTRACT

In an open-end spinning apparatus loose fibers are fed into a spinning rotor in which they are spun into a yarn that is continuously and axially withdrawn from the spinning chamber of the spinning rotor. The yarn length under formation continuously rotates in the spinning chamber about the spinning rotor axis and is at all times within the effective zone of an air drain means of which impurities leaving the yarn length under formation are removed from the spinning chamber. The air drain is generated by drawing air through an annular suction opening which communicates with the spinning chamber and which spacedly surrounds the spinning rotor axis.

United States Patent 1191 1111 3,859,779

Furstenberg Jan. 14, 1975 METHOD OF AND APPARATUS FOR 3,77 8"" 6/1969 Collins 57/58.89 0PEN.EN]) SPINNING 3,557,542 1/1971 Oskin et al 57/58.89 3,739,565 6/1973 N l 57 56 X [75] Inventor: Joachim Furstenberg, Aichelberg, age I Germany Primary Examiner-John Petrakes [73] Assignee: LTG Luittechnische GmbH, Attorney, g or irmE wi11 E. Gr igg Stuttgart, Germany 22 Filed: Nov. 6, 1972 [57] ABSTRACT [21] A I NO 303 714 In an open-end spinning apparatus loose fibers are fed into a spinning rotor in which they are spun into a yarn that is continuously and axially withdrawn from [30] Foreign Application Priority Data the spinning chamber of the spinning rotor. The yarn Nov. 5, 1971 Germany 2155171 length under formation Continuously rotates in the spinning chamber about the spinning rotor axis and is [52 us. c1 57/58.89, 57/56, 57/156 at all times Within the effective Zone of an drain [511 1111. C1. ..n0111 1/12, DOlh 11/00 means of which impurities leaving the y length [5 i ld f Search 56 under formation are removed from the spinning chamher. The air drain is generated by drawing air through [56] References Cited an annular suction opening which communicates with UNITED STATES PATENTS the spinning chamber and which spacedly surrounds the spinning rotor axis. 3,163,976 1/1965 Juillard 57/58.89 3,370,413 2/1968 Rajnoha et al 3,439,488 4/1969 Buci] et a1 57/58.95 10 Claims, 4 Drawing Figures fi l i l 9 l K l l I l l l /11 l l l l 9 32 13- v 25 15 1 5 1.5 H 21 3O H l PATENTEDJAH 1 4:975

SHEET 10? 2 PATENTEB JAN 1 41975 SHEET 2 OF 2 METHOD OF AND APPARATUS FOR OPEN-END SPINNING BACKGROUND OF THE INVENTION This invention relates to a method of and apparatus for open-end spinning, wherein the fibers are introduced into a spinning chamber formed by the inner space of a driven spinning rotor. In the spinning chamber the fibers are deposited into a fiber groove of the spinning rotor and are subsequently fed into the open end of a yarn which is continuously drawn off through a central yarn outlet channel. In this manner, the fibers spun into the end of the yarn continuously form a new yarn. The yarn length under formation (extending radially from the fiber groove towards the inlet of the yarn outlet channel) rotates in the spinning chamber about the axis of the spinning rotor. This rotary motion of said yarn length may be roughly compared to the motion described by the radius of a circle rotating in the plane of the circle about the center thereof. Usually a plurality of the afore-outlined spinning apparatuses are included in an open-end spinning machine.

In open-end spinning, the cleaning and clean operation of the spinning chamber and the spinning rotor are important considerations. There are various known devices which serve this purpose. These known devices, however, require an interruption of the spinning process for cleaning the spinning chamber or the spinning rotor or they adversely affect the spinning process.

OBJECT, SUMMARY AND ADVANTAGES OF THE INVENTION It is an object of the invention to provide in open-end spinning a method and an apparatus for improving the clean run of the spinning chamber and particularly the fiber groove of the spinning rotor and also for improving the quality of the yarn.

Briefly stated, according to the invention, the yarn length under formation, as it travels from the fiber groove of the spinning rotor to the central yarn outlet channel, passes through at least one air drain circularly and spacedly surrounding the axis of the spinning rotor. The air drain in which during normal operation there is always situated a loosely twisted length portion of the yarn, is generated by continuously withdrawing air at an angle to the travelling path of the yarn under formation. The withdrawal of air is effected by means of a vacuum source disposed at a distance downstream of an air slot (suction opening) adjoining the inside of the peripheral wall of the spinning rotor.

Without taking advantage of the measure according to the invention, impurities such as dust, fiber fragments or the like are not taken out of the spinning chamber and thus they may return from the yarn under formation into the fiber groove of the spinning rotor, so that the inner wall of the spinning rotor and the fiber groove are very rapidly soiled and coated with a tacky film. Or, the impurities may be drawn again into the yarn under formation and then are either again thrown back into the fiber groove or remain in the yarn and thus adversely affect its quality. In contradistinction, by passing the yarn under formation through the aforenoted air drain, the impurities are entirely or at least to a substantial extent drawn away permanently from the spinning chamber. Consequently, by virtue of the measure according to the invention, not only a clean operation of the spinning chamber and the spinning rotor is ensured, but also the quality of the yarn is improved.

The provision of an air drain according to the invention has the further advantage significant from the point of view of spinning technology that the air drain straightens and parallelizes those fibers or fiber ends that are at a distance from the location where the yarn formation takes place and thus are not yet grasped by the rotating yarn. In this respect too, there results a qualitative improvement of the manufactured yarn.

It is a further advantage of the air drain provided according to the invention, that it improves the cooling of the spinning chamber. In this manner an advantageous conditioning of the fibers is effected and, as a result, the quality of the yarn is further improved.

The invention will be better understood as well as further objects and advantages will become more apparent from the ensuing detailed specification of several exemplary embodiments taken in conjunction with the drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a sectional side elevational view of an openend spinning apparatus incorporating a preferred embodiment of the invention;

FIG. 2 is a schematic plan view of one component of the apparatus illustrated in FIG. 1;

FIG. 3 is a view similar to FIG. 2 illustrating another embodiment of the invention; and

FIG. 4 is a view similar to FIG. 2 showing still another embodiment of the invention.

DESCRIPTION OF THE EMBODIMENTS Turning now to FIGS. 1 and 2, the open-end spinning apparatus has a schematically shown housing 10 which has an inner chamber 13 communicating through two parallel spaced suction ducts 11 with a suction channel 12. In the chamber 13 there is disposed a spinning rotor 14 of conventional structure. The latter has at its inner side a circular fiber groove 15 into which the individual fibers which travel from a fiber opening apparatus (not shown) are deposited through a fiber guiding channel 17 by pneumatic means. The spinning rotor 14 is driven with a high rpm by an electromotor (not shown). The inside of the spinning rotor 14 which at its lower side is bounded by a stationary component generally indicated at 24, forms a spinning chamber 19 in which a yarn 20 is formed from the individual fibers as these leave the fiber groove 15 into which they had been deposited earlier. The yarn 20 is continuously drawn away through a yarn outlet channel 22 passing through a housing closure 21. The yarn 20 is continuously withdrawn from the spinning chamber 19 by means of a drawing roll pair 23 with constant speed through the yarn outlet channel 22 which is coaxial with the rotary axis of the spinning rotor 14.

The yarn 20 is, along a length portion where it is under formation and where it has only a slight twist, guided at a small distance over the stationary member 24 which has an annular suction opening 25 positioned concentrically with respect to the rotational axis of the spinning rotor (and is thus also concentric to the axis of the yarn outlet channel 22). In this embodiment the annular suction opening 25 is coplanar with the inlet opening 27 of the yarn outlet channel 22. The annular suction opening 25 is, at its inner (smaller) circumference bounded by the circular outer edge of a disc 28 forming part of the stationary member 24 and at its outer (larger) circumference is bounded by the inner circular edge of an annularly shaped elevation 29 of the closure 21. The elevation 29 also forms part of the stationary component 24. The suction opening 25 leads directly into an annular suction chamber 30 which spacedly surrounds the yarn outlet channel 22. The suction chamber 30 communicates with a vacuum source 32 through a channel 31. Upstream of the vacuum source 32 there is positioned a filter 33 for separating impurities contained in the air drawn thereby. In the channel 31 there is further arranged a throttle gate 34 for the selective opening and closing of the channel 31, so that when the spinning of the yarn is started anew subsequent to yarn breakage or subsequent to the starting of the machine, withdrawal of air through the annular suction opening 25 may be temporarily interrupted in order to make possible or facilitate the start or restart of the spinning operation. During normal operation the gate 34 is in a predetermined, fully or partially open position which is adjusted dependent upon the desired force of the air suction.

When air is drawn into the suction opening 25, there is generated thereabove in the spinning chamber an air drain (that is, a field of flowing air) in which the flow velocity of the air rapidly increases in the direction of the suction opening 25. The yarn 20 is, with a length portion still having only a loose twist, guided at a small distance over the suction opening 25. It is feasible, however, to permit the yarn in some cases to lie against the edges of the suction opening 25; this possibility, however, is not illustrated in the drawing. As the yarn portion under formation rotates about the axis of the spinning rotor 14, it continuously travels above the suction opening 25 in the circumferential direction thereof. Since the suction opening 25 is of annular, circular configuration, the yarn remains, despite its aforenoted rotation about the axis of the spinning rotor, continuously in the zone of the air drain generated by the air drawn into the suction opening 25.

During normal operation, the vacuum in the suction chamber 30 is stronger than the vacuum in the spinning chamber 19. The suction opening 25, which, as noted before, forms a circular annular gap is so dimensioned that along the entire suction opening the effective depth of the air drain is approximately uniform. As a result, the yarn continuously moves in an air drain of approximately constant effective depth.

The width of the suction opening measured in the radial direction with respect to the spinning rotor axis is not critical. Advantageous dimensions may be easily determined by tests. Thus, this width may be, for example, one-third to one-eighth the length of the radius of the circle described by the fiber groove 15 and the outer edge of the suction opening 25 may be, for example, at a distance of -20 mm from the fiber groove 15.

The suction effect of the air drain in the zone of the yarn under formation is to be set by approximate selection of the vacuum prevailing in the suction chamber 30 in such a manner that impurities such as dust, fiber fragments and the like which have not been removed by pre-cleaning means (not shown) upstream of the loose twist of the yarn portion in the zone of its formation, the impurities are not firmly embedded therein and thus they separate with relative ease. These impurities then pass through the suction chamber 30 and the channel 31 and arrive to the filter 33 where they are separated from the air stream.

An advantageous magnitude of the differential pressure that generates the air drain may also be determined by tests in a simple manner in each case. For example, good results were obtained in an experimental structure with differential pressures between 5 and 10 mm water column pressure. The selection of optimal values is affected by the particular structure of the apparatus, yarn properties and the like.

The afore-described suction system may be combined with a further suction system which draws the fibers into the spinning chamber 19 through the conduit 17 and which may also have other functions, for example, a cleaning of the spinning chamber or returning the yarn into the spinning chamber subsequent to a yarn breakage or the like. The vacuum source of this additional suction system may be formed in a known manner by the spinning rotor itself and/or a separate, preferably a central vacuum source 32 which draws air through the suction channel 12 and which, together with the filter serves all the open-end spinning devices of the entire machine.

In the channels 11 there are situated angularly adjustable throttle gates 49 in order to adjust the strength of the air stream passing through these channels and thus to adjust the strength of the air stream passing through the annular air gap 45 formed by the outer peripheral wall of the elevated portion 29 and the inside of the circular terminal wall 44 of the spinning rotor 14. By means of the throttle gates 34 and 49, the ratio of the air quantities passing through the channels 11 to the air quantities passing through the suction opening 25 may be set to an optimal value.

The filter 33 may be expediently designed in such a manner that it is continuously cleaned. Or, it may be of the type which may be replaced without interrupting the operation of the machine.

It has further been found advantageous to so select the speed with which the fibers are admitted through the fiber supply tube 17 into the fiber groove 15 that, at the moment of their arrival into the fiber groove, it is smaller than the circumferential speed of the fiber groove in order to achieve a parallel and linear deposition of the fibers in the direction of rotation of the fiber groove 15.

Turning now to the embodiment illustrated in FIG. 3, the disc 28 is arranged eccentrically with respect to the outer edge of the annular projection 29. The width of the suction opening 25' formed in this manner decreases from a maximum value at a first location which is diametrically opposite the inlet of the yarn outlet channel 22 and reaches a minimum value at a second location which is diametrically opposite the first location. The inner and outer edges of the suction opening 25' are both, similarly to the embodiment of FIG. 2, of circular configuration. By means of the embodiment according to FIG. 3 it is possible to set the said effective depth of the air drain in a simple manner to an approximately constant value if, with an annular suction opening of uniform width (FIG. 2) there cannot be achieved a sufficiently constant effective depth of the air drain.

Turning now to FIG. 4, there is shown a further advantageous modification of the suction opening. This embodiment may find application either in case of an eccentric arrangement of the inner edge of the circular suction opening relative to the outer edge thereof and- /or in case of a concentric arrangement of these two edges. In FIG. 4, the suction opening that generates the air drain is designated at 50 and has, for improving the yarn formation and for intensifying the cleaning effect, in addition to an annularly shaped suction zone 25", a circular array of radial suction openings 51 which extend inwardly from the annular range 25" of the suction opening 50. The radial suction openings 51 are provided in the disc 28. The entire cross section of the suction opening (the annular section 25" and the radial slots 51) is selected in such a manner that there are obtained uniform suction conditions, that is, there is obtained a uniform air drain through which the yarn range under formation travels as it rotates about the axis of the spinning rotor 14.

It is to be understood that it is within the scope of the invention to provide, instead of a contiguous annular suction opening a plurality of openings, (for example, segmental openings) which have the approximate overall effect of a sole annular suction opening. Instead of a single annular air drain it isalso feasible to provide two or more concentrically arranged air drains.

What is claimed is:

1. In a method of open-end spinning of the type including the known steps of (a) feeding loose fibers into an annular fiber groove of a rotating portion of a spinning chamber, (b) depositing said loose fibers into a circular fiber groove provided in the wall of the rotating portion of the spinning chamber, (c) spinning a yarn from the fibers by virtue of the rotation of the spinning chamber, and (d) continuously withdrawing the spun yarn substantially coaxially with the rotary axis of the spinning chamber, any portion of said yarn describing simultaneously a motion from said fiber groove to said axis and a rotary, orbiting motion thereabout, the improvement comprising the step of generating an annular air drain spacedly surrounding the rotary axis by forming an annular opening in a stationary portion of the spinning chamber, the annular opening being so positioned that at any instant during the travel of the yarn in the spinning chamber a yarn length having a loose twist is within the zone of said air drain, and that the air flow in said air drain is at an angle to the travelling path of the yarn in the spinning chamber.

2. In an open'end spinning apparatus of the known type that has (a) a spinning rotor having a hollow interior constituting a spinning chamber, said spinning rotor having a circular terminal wall bounding said spinning chamber, (b) a fiber groove provided circumferentially in the wall of said spinning chamber, (0) means feeding loose fibers into said spinning chamber and depositing them into said fiber groove, said feeding means terminating in said spinning chamber substantially adjacent said fiber groove, (d) means for continuously withdrawing yarn from said spinning chamber substantially coaxially with the axis of said spinning rotor, said last-named means including a yarn outlet channel substantially coaxial with said axis, wherein said yarn is spun from said fibers by virtue of the rotation of said spinning rotor, and wherein said yarn describes a rotary motion in said spinning chamber about said axis, the improvement comprising A. means stationarily supported with respect to said spinning rotor defining in said spinning chamber an annular suction opening spacedly surrounding the rotary axis of said spinning rotor and disposed adjacent the travelling path of said. yarn in said spinning chamber, said annular suction opening being spaced from said circular terminal wall.

B. conduit means communicating with said spinning chamber through said annular suction opening and C. a vacuum source in said conduit means downstream of said suction opening to generate an air drain in said spinning chamber, at least an annular zone of said travelling path contained in said air drain.

3. An improvement as defined in claim 2, including means for generating a uniform effective depth of said air drain.

4. An improvement as defined in claim 2, said spinning chamber having an open side, said means defining said annular suction opening extending into said spin ning chamber through said open side.

5. An improvement as defined in claim 2, including A. a housing defining a housing chamber for accommodating said spinning rotor and B. further conduit means communicating with said housing chamber and connected to said vacuum source for continuously drawing air from said housing chamber.

6. An improvement as defined in claim 2, including means for controlling the intensity of suction generated by said vacuum source.

7. An improvement as defined in claim 6, said lastnamed means including throttle means disposed in said conduit means.

8. An improvement as defined in claim 2, said yarn outlet channel having an inlet opening in said spinning chamber, said annular suction opening being situated at about the same height as said inlet opening.

9. An improvement as defined in claim 2, including means defining a circular array of suction slots extend ing radially from said annular suction opening.

10. In an open-end spinning apparatus of the known type that has (a) a spinning rotor having a hollow interior constituting a spinning chamber, said spinning rotor having a circular terminal wall bounding said spinning chamber, (b) a fiber groove provided circumferentially in the wall of said spinning chamber, (c) means feeding loose fibers into said spinning chamber and depositing them into said fiber groove, said feeding means terminating in said spinning chamber substantially adjacent said fiber groove, (d) means for continuously withdrawing yarn from said spinning chamber substantially coaxially with the axis of said spinning rotor, said last-named means including a yarn outlet channel substantially coaxial with said axis, wherein said yarn is spun from said fibers by virtue of the rotation of said spinning chamber, and wherein said yarn describes a rotary motion in said spinning chamber about said axis, the improvement comprising A. means stationarily supported with respect to said spinning rotor defining a plurality of suction openings in said spinning chamber adjacent the travelling path of said yarn,

B. conduit means communicating with said spinning chamber through said suction openings and C. a vacuum source in said conduit means downstream of said suction openings to generate at least one air drain in said spinning chamber in a zone of said travelling path, the shape of said air drain being such that a length portion of said yarn is within said air drain at any point of its travel. l l

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 859 779 Dated January 14 1975 Inventor(s) Joachim Fflrstenberg It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the ABSTRACT, line 7, insert --byafter "drain".

Column 4, line 11, after "between", "5 and 10" should be -5l0.

Signed and Scaled this A lies I" RUTH C. MASON C. MARSHALL DANN Amxrmg Officer Commissioner of Parenls and Trademarks ORV PO-IOSO (10-69 USCOMM-DC 60375=P69 u s GC-VERNMEN'! PRINTJNG otncer 93 O 

1. In a method of open-end spinning of the type including the known steps of (a) feeding loose fibers into an annular fiber groove of a rotating portion of a spinning chamber, (b) depositing said loose fibers into a circular fiber groove provided in the wall of the rotating portion of the spinning chamber, (c) spinning a yarn from the fibers by virtue of the rotation of the spinning chamber, and (d) continuously withdrawing the spun yarn substantially coaxially with the rotary axis of the spinning chamber, any portion of said yarn describing simultaneously a motion from said fiber groove to said axis and a rotary, orbiting motion thereabout, the improvement comprising the step of generating an annular air drain spacedly surrounding the rotary axis by forming an annular opening in a stationary portion of the spinning chamber, the annular opening being so positioned that at any instant during the travel of the yarn in the spinning chamber a yarn length having a loose twist is within the zone of said air drain, and that the air flow in said air drain is at an angle to the travelling path of the yarn in the spinning chamber.
 2. In an open-end spinning apparatus of the known type that has (a) a spinning rotor having a hollow interior constituting a spinning chamber, said spinning rotor having a circular terminal wall bounding said spinning chamber, (b) a fiber groove provided circumferentially in the wall of said spinning chamber, (c) means feeding loose fibers into said spinning chamber and depositing them into said fiber groove, said feeding means terminating in said spinning chamber substantially adjacent said fiber groove, (d) means for continuously withdrawing yarn from said spinning chamber substantially coaxially with the axis of said spinning rotor, said last-named means including a yarn outlet channel substantially coaxial with said axis, wherein said yarn is spun from said fibers by virtue of the rotation of said spinning rotor, and wherein said yarn describes a rotary motion in said spinning chamber about said axis, the improvement comprising A. means stationarily supported with respect to said spinning rotor defining in said spinning chamber an annular suction opening spacedly surrounding the rotary axis of said spinning rotor and disposed adjacent the travelling path of said yarn in said spinning chamber, said annular suction opening being spaced from said circular terminal wall. B. conduit means communicating with said spinning chamber through said annular suction opening and C. a vacuum source in said conduit means downstream of said suction opening to generate an air drain in said spinning chamber, at least an annular zone of said travelling path contained in said air drain.
 3. An improvement as defined in claim 2, including means for generating a uniform effective depth of said air drain.
 4. An improvement as defined in claim 2, said spinning chamber having an open side, said means defining said annular suction opening extending into said spinning chamber through said open side.
 5. An improvement as defined in claim 2, including A. a housing defining a housing chamber for accommodating said spinning rotor and B. further conduit means communicating with said housing chamber and connected to said vacuum source for continuously drawing air from said housing chamber.
 6. An improvement as defined in claim 2, including means for controlling the intensity of suction generated by said vacuum source.
 7. An improvement as defined in claim 6, said last-named meAns including throttle means disposed in said conduit means.
 8. An improvement as defined in claim 2, said yarn outlet channel having an inlet opening in said spinning chamber, said annular suction opening being situated at about the same height as said inlet opening.
 9. An improvement as defined in claim 2, including means defining a circular array of suction slots extending radially from said annular suction opening.
 10. In an open-end spinning apparatus of the known type that has (a) a spinning rotor having a hollow interior constituting a spinning chamber, said spinning rotor having a circular terminal wall bounding said spinning chamber, (b) a fiber groove provided circumferentially in the wall of said spinning chamber, (c) means feeding loose fibers into said spinning chamber and depositing them into said fiber groove, said feeding means terminating in said spinning chamber substantially adjacent said fiber groove, (d) means for continuously withdrawing yarn from said spinning chamber substantially coaxially with the axis of said spinning rotor, said last-named means including a yarn outlet channel substantially coaxial with said axis, wherein said yarn is spun from said fibers by virtue of the rotation of said spinning chamber, and wherein said yarn describes a rotary motion in said spinning chamber about said axis, the improvement comprising A. means stationarily supported with respect to said spinning rotor defining a plurality of suction openings in said spinning chamber adjacent the travelling path of said yarn, B. conduit means communicating with said spinning chamber through said suction openings and C. a vacuum source in said conduit means downstream of said suction openings to generate at least one air drain in said spinning chamber in a zone of said travelling path, the shape of said air drain being such that a length portion of said yarn is within said air drain at any point of its travel. 